Introduction: The aim of the present study was to evaluate the clinical usefulness of riboflavin- and ultraviolet-A (UV-A)-induced collagen cross-linking (CXL) on progressive keratoconus.
Patients and methods: Twenty eyes of 20 patients with progressive keratoconus were included in a prospective, nonrandomized pilot study. The preoperative progression of keratoconus was documented by an increase in maximum keratometry (Kmax) on serial corneal topographies. Preoperative corneal thickness was at least 400 microm. The postoperative progression of keratoconus was evaluated from corneal topography, best-corrected visual acuity (BCVA) testing, and corneal biomechanical properties assessed with the Ocular Response Analyzer (ORA). The follow-up time was between 3 and 18 months.
Results: The steepening decreased significantly by 1.68+/-2.18 diopters (D) in the first year (p<0.05). The Kmax value decreased in 66% of eyes and remained stable in 17% (within+/-0.50 D). The mean preoperative BCVA was 0.49+/-0.22. Six months after the CXL treatment, the mean BCVA was 0.63+/-0.23 (p<0.05) and improved at least one line in 56.25% of eyes. The ORA values remained stable over the entire follow-up period.
Discussion: Extensive experimental study showed a significant increase in corneal rigidity after riboflavin/UV-A-induced CXL.
Conclusion: Preliminary results on the clinical effects of riboflavin/UV-A-induced CXL are encouraging in reducing the progression of keratoconus. Long-term results are necessary to evaluate the duration of the stiffening effect.